#!/usr/bin/env python3

"""

# Purpose: Produce a CSV file showing groups with only external members, i.e, those in domains other than ones you specify.

# Customize: DELIMITER, DOMAIN_LIST, AGGREGATE_DOMAINS

# Python: Use python or python3 below as appropriate to your system; verify that you have version 3

# $ python -V or python3 -V

# Python 3.x.y

# Usage:

# 1: Get group members

# $ gam redirect csv ./GroupMembers.csv print group-members fields email,type

# 2: From that list of group members, output a CSV file with headers group,domain,count

# $ python3 GetGroupsWithOnlyExternalMembers.py ./GroupMembers.csv ./GroupsWithOnlyExternalMembers.csv

"""

import csv

import sys

DELIMITER = ' ' # Character to separate domains in output CSV

QUOTE_CHAR = '"' # Adjust as needed

LINE_TERMINATOR = '\n' # On Windows, you probably want '\r\n'

# Substitute your internal domain(s) in the list below, e.g., DOMAIN_LIST = ['domain.com',] DOMAIN_LIST = ['domain1.com', 'domain2.com',]

DOMAIN_LIST = ['domain.com',]

# False - show one group/one external domain per line

# True - show one group/all external domains per line

AGGREGATE_DOMAINS = True

if (len(sys.argv) > 2) and (sys.argv[2] != '-'):

outputFile = open(sys.argv[2], 'w', encoding='utf-8', newline='')

else:

outputFile = sys.stdout

outputCSV = csv.DictWriter(outputFile, ['group', 'domain', 'count'], lineterminator=LINE_TERMINATOR, quotechar=QUOTE_CHAR)

outputCSV.writeheader()

if (len(sys.argv) > 1) and (sys.argv[1] != '-'):

inputFile = open(sys.argv[1], 'r', encoding='utf-8')

else:

inputFile = sys.stdin

inputCSV = csv.DictReader(inputFile, quotechar=QUOTE_CHAR)

Groups = {}

GroupsWithInternalMembers = set()

for row in inputCSV:

if row['type'] in ['USER', 'GROUP']:

group = row['group']

emailAddress = row['email'].lower()

atLoc = emailAddress.find('@')

if atLoc > 1:

domain = emailAddress[atLoc+1:]

else:

domain = 'unknown'

if domain not in DOMAIN_LIST:

Groups.setdefault(group, {})

Groups[group].setdefault(domain, 0)

Groups[group][domain] += 1

else:

GroupsWithInternalMembers.add(group)

for group, domains in sorted(iter(Groups.items())):

if group in GroupsWithInternalMembers:

continue

if not AGGREGATE_DOMAINS:

for domain, count in sorted(iter(domains.items())):

outputCSV.writerow({'group': group,

'domain': domain,

'count': count})

else:

total = 0

domainsList = []

for domain, count in sorted(iter(domains.items())):

domainsList.append(domain)

total += count

outputCSV.writerow({'group': group,

'domain': DELIMITER.join(domainsList),

'count': total})

if inputFile != sys.stdin:

inputFile.close()

if outputFile != sys.stdout:

outputFile.close()